Notes4:InternetworkingHierarchicalModel - echadbourne/NET-330 GitHub Wiki

What do we need to plan for?

Physical equipment

Equipment placement and connectivity

IP addressing and subnet design

Network security and segmentation

Hierarchical Internetworking Model: Multi-tier architecture divides enterprise networks into three for layers

End stations and servers connect to the enterprise at the access layer
Access layer devices are usually commodity switching platforms (aka switches and wireless access points)
This layer is also called the desktop layer because it focuses on connection client nodes, such as workstations to the network
Layer 2 Technology like VLANs

The smart layer in the three-layer model
Routing, filtering (internal firewalling) and QoS policies are managed at the distribution layer
Distribution layer devices also often manage individual branch-office WAN connections
Typically handled by Multi-Layer switches (aka - switches that route)

So "Layer 3 switches" meaning that they can also deal with IP addresses

Provides high-speed, highly redundant forwarding services to move packets between distribution layer devices in different regions of the network
Core switches and routers are usually the most powerful, in terms of raw forwarding power in the enterprise
Core network devices manage the highest-speed connections, such as 10,40, or 100 gbps
however they are typically pretty dumb - just switching (layer 2)
Often dont need much configuration - just links the distribution layers to each other - and to the Border

AKA - Network Backbone

Simply the network devices that connect an enterprise network to the internet
Routers, border firewall, border load balancers, border IPS and other security devices
Layer 3 and up